Properties of equality:
Reflexive property:
For all real values x, we have that x = x, that is, a number is equal to itself.
Symmetric:
If x = y, then y = x.
Transitive:
If x = y and y = z, then x = z.
Addition:
If x = y, then x + z = y + z
Subtraction:
If x = y, then x - z = y - z.
Multiplication:
If x = y, then xz = yz
Division:
If x = y, then x/z = y/z
Substitution:
If x = y, then x can be replaced by y in any expression.
Distributive:
Distributive: x(y+z) = xy + xz
In this question:
Step 2:
We subtract 5 on both sides, so we apply the subtraction property.
Step 4:
We multiply both sides by 4, so we apply the multiplication property.